1. Field of Invention
The present invention relates to a device, components, or the like for use in information communication (signal transmission) by optical signals between a plurality of devices or inside of a device.
2. Description of Related Art
In recent years, a signal transfer rate between circuit chips included in various devices, or between circuit boards has increased, and problems such as crosstalk between signal lines, noise radiation, impedance mismatch and high power consumption have become critical. Consequently, optical communication has started to be introduced in signal transmission between circuit chips inside of a device, between modules or the like. Therefore, a technique of transmitting an optical signal via an optical transmission path, such as optical fiber (tape fiber) or optical waveguide for communication in place of a conventional method of transmitting an electrical signal via metal wiring has been employed. For example, such a technique is described in “NIKKEI ELECTRONICS”, Nikkei BP Publications, Inc., Dec. 3rd, 2001 issue, pages 112–122.
When performing optical communication, it is important to perform mutual alignment (optical-axis alignment) with higher precision at coupling points existing on an optical signal transmission path, such as between optical fibers and between an optical fiber and a light-emitting element, or a light-receiving element to avoid an increase of optical coupling loss. In order to satisfy such a demand, various techniques are employed. One of these techniques is described, for example, in Japanese laid-open patent publication No. 7-49437.
In case of optical connectors described in Japanese laid-open patent publication No. 7-49437, when one connector is provided with a fitting pin and the other connector is provided with a fitting hole into which the fitting pin is inserted, there is a disadvantage that miniaturization is difficult.
Furthermore, a photo-electric conversion module described in “NIKKEI ELECTRONICS”, Nikkei BP Publications, Inc., Dec. 3rd, 2001 issue, pages 112–122 has a configuration in which an end surface of an optical fiber (optical transmission path) is directly arranged on a light-emitting surface or a light-receiving surface of an optical element via a small-sized connector (optical plug). Consequently, when the small-sized connector is removed, the light-emitting/light-receiving surface of the optical element and the end surface of the optical fiber are exposed, which is apt to cause defects, such as damage of the light-emitting surface or the like and adhesion of foreign materials.